The process for chlorinating titanium containing materials in a fluidized bed reactor is known. Suitable processes are disclosed in the following U.S. Pat. Nos. 2,701,179; 3,883,636; 3.591333; and 2,446,181. In such processes, particulate coke, particulate titanium bearing materials, chlorine and optionally oxygen or air are fed into a reaction chamber, and a suitable reaction temperature, pressure and flow rates are maintained to sustain the fluidized bed. Gaseous titanium tetrachloride and other metal chlorides are exhausted from the reaction chamber. The gaseous titanium tetrachloride so produced can then be separated from the other metal chlorides and exhaust gas and used to produce titanium dioxide, titanium metal or titanium containing product.
In the chlorination process to prepare titanium tetrachloride, TiCl4, in a fluidized bed reactor, it is desirable to reduce or control the formation of excess silicon tetrachloride and other undesirable chlorinated organic species. Silicon tetrachloride, SiCl4, contamination of titanium tetrachloride impacts a variety of quality parameters, such as particle size distribution and primary particle size (indicated by carbon black undertone) of the titanium dioxide produced by oxidation of the TiCl4. Minimizing or controlling the silica contamination allows for improved performance of the TiO2 product.
A need exists for a control process that detects the presence of excess SiCl4, and therefore excess silica in the final product, and that is capable of correcting the problem.